QuickTime Layers - Core Animation - page 112

The QTMovie object from QTKit provides all you need for movie control, such as playback,
scrubbing, fast forward, and so on. The difference is that QTMovie doesn't have the visual
elements that QTMovieView does. Instead, you must tie your actions to outlets such as
sliders and buttons. The action methods available to you in QTMovie are listed in Table 7-1.

Table 7-1 QTMovie's Action Methods

Method Description

autoplay does the same thing as play except it is for
use with streaming media. It will only start playing
back the movie when enough data is available.

- autoplay

Begins movie playback.

- play

Stops movie playback. - stop

Sets the currentTime field in the QTMovie object to
QTMovieZero , the movie beginning.

- gotoBeginning

Sets the currentTime field in the QTMovie object to
match the movie duration.

- gotoEnd

If a selection point has been set in the QTMovie
object, sets the currentTime field to that selection
point.

- gotoNextSelectionPoint

If a selection point has been set in the QTMovie
object, sets the currentTime field to that selection
point if that time is prior to the currentTime field's
time.

- gotoPreviousSelectionPoint

Sets the currentTime field in the QTMovie object to
the poster frame time. If no poster frame is specified,
currentTime is set to the beginning of the movie.

- gotoPosterFrame

Sets the currentTime field in the QTMovie object to
the QTTime you specify as a parameter.

- setCurrentTime:

Advances the movie ahead by one frame. The
currentTime field is updated accordingly.

- stepForward

Steps the movie back by one frame. The currentTime
field is updated accordingly.

- stepBackward

You can simply create an IBAction method in your controller and call any of these
methods from those actions. See the upcoming section, “Adding Basic Playback
Controls,” to see how this is done.

Creating a Simple QTMovieLayer-Based Player
In the sample project for this chapter called Movie Player with Overlay (on the compan-
ion website), we created an application delegate class, called AppDelegate , that we associ-
ated with a controller object in Interface Builder. With this set up, the AppDelegate class
gives us an entry point to create and display the QTMovieLayer . In this project, in addi-
tion to the QuartzCore framework, we added the QTKit framework. It is located at